Asset repositories from Valve games have been leaked online.
According to PC Gamer, this is the biggest asset leak in the company's history, impacting titles such as Half Life 2 (including files related to its multiplayer), Portal, Team Fortress 2, and Counter Strike: Source, among others.
It doesn't look like any files from upcoming and/or unannounced games have been leaked.
source https://www.gamesindustry.biz/valves-assets-from-portal-half-life-2-and-more-leak-online
